A major objective of this invention is to provide a drawer building machine which is as automatic as can be in its operation when working with the various drawer styles.
Drawers are designed in many styles. One style is a drawer in which the front has two recesses spaced inwardly from the ends that receive the sides in which case the sides are secured in my machine by staples diagonally driven through the sides into the front from the rear side of the front. The rearward side of such a drawer is received in notches on the inner sides of the sides at the rearward ends, these notches opening also on the rearward ends of the sides, as distinguished from the notches in the front, which only open rearwardly. The rear panel in such a drawer is received in the notches and the staples are driven at a 90 degree angle through the sides into the rear panel.
The bottom of the drawer is first slid into place between the sides and into a groove at the front, such bottom receiving grooves being normally adequate to hold the bottom in place, in addition to a similar groove at the bottom of a rearward side of the drawer which receives the back side of the bottom piece.
One of my concepts is to build a drawer in a machine with the front piece of the drawer facing downwardy, the sides extending vertically and put into place just before the manually sliding therebetween of a bottom piece and preceding the placement of the rear side piece of the drawer. I conceive that in this way of making the drawer the back piece is held in place by gravity before it is stapled in place, which leads to a possibility of an operator finding it simple to reach to the position in which he must slide the bottom piece in place, as contrasted to machines of the prior art in which the drawer is positioned in the machine with the bottom of the drawer downward so that the operator then must reach across the front side piece of the drawer clear to the rearward side of the drawer and awkwardly push the bottom piece in place by shoving it toward his stomach forwardly into the machine toward the front piece of the drawer.
An objective of my machine is to hold the drawer in a position so that the entire drawer is at a minimum distance from the operator's position at the front of the machine so that everything can be easily reached. This means that as the machine establishes positions for parts, the operator can manually put the parts in place very simply and with a minimum of reaching and stretching.
It is true that in the prior art there have been machines in which the front of the drawer is disposed rearwardly in the machine, whereby when the operator manually slides the bottom of the drawer in place he can push it in from the front side which in itself is not a disadvantage, but there is a great disadvantage at the earlier stage in which the front piece of the machine must be manually positioned by the operator by reaching deep down into the machine toward the rearward side of the machine to put the front piece to the rear of the machine in the first place, a reaching and stretching which I propose to avoid for advantages of speed of operation, and less tiring out of the operator.
Another disadvantage of the above described prior art type of drawer building machine is that when the front piece is at the rear of the machine the inevitable result is that the back piece of the drawer is then at the front of the machine and extra mechanism is required to support it; whereas, in my machine this first drawer style can be made with the advantage that the back piece of the drawer is vertically supported by notches in the sides of the drawer by gravity alone and without special mechanism.
A second drawer style is the one I make by placing the front of the drawer at the lower position in the machine, a characteristic of the making of all drawers in my machine, the front of the drawer in this second style having notches that open toward the rearward side of the front and also toward its ends, receiving therein the forward ends of the side pieces of the drawer with the rear side of the drawer put in place last. But in this style of drawer there are no notches at the rear of the side pieces of the drawer to receive the back piece and I provide pneumatic mechanism to support the rearward edge of the back side piece of the drawer from falling downward during stapling, the forward side of the back piece of the drawer, as it is seen in the machine, being supported by the bottom piece of the drawer previously put into place and needing no mechanical supportt. This is contrasted with the prior art because the underside of the drawer back piece needs to be supported only from its underside since gravity alone is sufficient to hold it in place on its upper side in the machine, as contrasted with the placement of pieces in the prior art in which a back piece must be supported from what will later be the inner side of the back piece and also in addition from what will later be the back side of the back piece in order to keep it from tipping over.
A third style of drawer has side walls and a bottom piece that make a box having one side open that will later be the top of the drawer, and a drawer front piece is later added to this box, which is fixed to the front piece of the box as a later step. Such drawers are used in the prior art because such a "drawer box" can be made in quantity and then various lengths and widths of the front piece can be added to them as desired for different articles of furniture.
In making the drawer of this third style in my machine the front piece to be later added is not present in the machine at all, by my concept, and in its place a mock front piece is placed in the machine as a temporary size gauge for the machine to sense the later position of a front piece from, so that all the parts of the "box" come into the right place.
These mock front pieces of my method can be called front piece templates, as long as the same size drawer is being made, the same front piece template stays in place. When another size drawer is made that template is replaced with a template of a different size.
In the prior art, the making of this third style was difficult, because the noses of the stapling guns were used to hold the side pieces of the drawer in place prior to stapling. This would appear to be of no disadvantage, but it is my concept that this is a great disadvantage, because by eliminating this double use of the stapling guns themselves and by positioning the side pieces of the drawer by other means than the stapling guns, I am then able to free the stapling guns for shifting movements which I call indexing, so that they can be automatically positioned by the programming of the machine to staple in just the right places for each drawer depth and so that I can provide many guns in a row, some of which, for a drawer of shallow depth, will not be in alignment with the drawer. My concept is to have these non-aligned guns automatically non-firing which is a great safety feature.
Another advantage of this freedom of the guns to be indexed, as is possible because they are not also used to hold the sides of the drawer in place during stapling, is the further advantage that the guns can be indexed to anticipate various drawer side heights, speaking of a right side up drawer as it is in a desk.
Another objective of this invention is to provide for the automatic shifting of the guns of a row simultaneously as a unit after the spacing between the guns has once been pre-set in the machine by the operator. This makes it possible to have the row of guns in first positions from which firing occurs, from only the guns which are opposite the drawer, since the guns not opposite the drawer will not fire because of safety sensing provisions of the machine. This first firing might put two staples into a drawer of lesser finished height, or three staples into a drawer of greater finished height, but since further staples may be desired in the drawer, the row of guns, therefore, automatically shifts in a direction parallel to the height of the finished drawer, so that in the second position one or more guns are opposite the drawer in firing staples in accordance with the finished height of the drawer. This all occurs without any separate manual steps by the operator in readjusting stapler gun positions as in the prior art because the whole row is automatically indexed to shift a pre-set amount. Even this amount of index shifting can be adjusted in dimension, for example, from one to two inches.
Another objective of this invention is to provide for the positioning of vertically shiftable gun supporting carriages by means not only of a single air pressure used to cause them to be supported at a certain level against the effect of gravity, but also to provide an extra air pressure source opposed to the first source to press the carriages downwardly. In the use of this extra pressure source, which is a new concept in jig stapling machines, to my knowledge, the upwardly pushing effect is accomplished by an air pressure that slightly more than compensates for the weight of the gun supporting carriage whereby a much lesser opposing pressure is used to hold the carriages downwardly into a precise position not not as precisely obtainable with a supporting pressure alone, using only gravity for the downward push.
In a sense, this increases the effect of atmospheric pressure on the top of the cylinder by replacing it with an additional pressure, which herein is called the opposing pressure. This opposed pressure system has two major advantages. The first major advantage is the precise positioning of the gun carriages that is afforded.
The second major advantage is that as the carriages move downward, they move under the influence of a very, very little pressure, so that if an operator's fingers were caught between parts where they might be smashed, it will be found that the amount of pressure being applied by the combination of the second opposing air pressure and gravity against the first and carriage opposing air pressure is so little as not to injure the operator's finger at all, whereby the net pressure on the operator's fingers might be two pounds or five pounds, but not an injuring amount.
In the control of horizontal motion of heavy machine parts so as to position a left carriage of the machine closer or farther from a right carriage, I cause the pressure that moves the left carriage toward the right carriage to remain constant so as to hold drawer pieces in place, remaining constant, that is, after a control button is released. But when the left carriage is to be moved away from the right carriage, then the pneumatic mechanism provides for the left carriage to continue to move away from the right carriage so long as the control button remains depressed. Also whenever the control button is released during movement of the left carriage out from the right carriage, then such release of the control button releases all pneumatic pressures effecting the left carriage so that it simply stops, which is a convenient feature because the left carriage can be jogged out from the right carriage to the amount desired. It is also a safety feature because it will not continue to move out away from the right carriage after the button is released because the latter could accidently pinch an operator's arm between the left carriage and frame.
A third advantage is that because the left carriage need not be moved all the way out to the end and then back in toward the right carriage in order to adjust its positioning, so if the new drawer size is only slightly larger than the drawer previously programmed, the left carriage can be moved only slightly outward and only slightly back inward, thus saving valuable time.
The automatic opening timing feature of the pneumatic circuit is such that after a drawer is finished the drawer positioning parts automatically retract and the left carriage itself automatically moves a short distance from the right carriage, the latter being a pre-set and an adjustable distance.